Juice Cleanses Aren’t Healthy After All

A decade ago, doctors and nutritionists were already sick of hearing about detoxes. Since the 1990s, the wellness crowd has been obsessed with cleansing, whether via celebrity-endorsed vegetable juice fasts or expensive commercial detox products supported by quasi-science. In a 2014 survey, 68 percent of registered dietitian nutritionists (RDNs) indicated a general increase in questions from clients about cleanse, juice, and detox diets. But 80 percent of those interviewed said they would not recommend any such program.

Most juice fasts, as well as many other commercial detox products, deprive you of nutrients that drive detoxification. One easy example: Decreasing or eliminating sources of protein limits the body’s ability to synthesize glutathione, often considered the body’s master detox enzyme. Without it, detoxification halts. For athletes, pausing the flow of diverse nutrients during a multiday detox regimen or any fad diet is unlikely to increase performance and is likely to have negative impacts, says Julie Stefanski, a Philadelphia-based RDN who has worked with athletes of different levels for more than 15 years.

“The longer that you do something like a juice fast, the more likely you’re missing out on something your body needs,” Stefanski says. Moreover, she explains, when protein intake drops, “you’re going to be breaking down your own muscle tissue along with fat, and the next time you go out and try to do the same activity, you might not have the same strength and energy you had before.”

Toxins are real, it’s just that cleanses aren’t the way to get rid of them. Your body—specifically, soft tissue, fat cells, and bones—can absorb harmful materials like airborne pollutants, heavy metals, and pesticides, which contribute to health issues ranging from fatigue to cancer. The body neutralizes toxins by transforming them during a series of biochemical reactions called “pathways.” The end product is a water-soluble form that is expelled via body fluids.

“The body detoxifies on its own, or we would be dead in days,” says Robin Foroutan, a RDN and spokesperson for the Academy of Nutrition and Dietetics. She certainly agrees that juice-cleanse quick fixes are not the answer, but she argues that we can still take steps to improve our detoxification system.Emerging research suggests that our diets may help or hinder our bodies’ effectiveness in processing harmful materials.

Enzymes are the catalysts that fire up the detoxification pathways—and your intake of certain vitamins, minerals, flavonoids, and amino acids can either fuel or starve them. Some RDNs and other health experts are concerned that common eating patterns are starving these enzymes. They worry that the modern diet lacks adequate nutrients for detoxification systems to function at their best. As researchers work to develop an evidence-based understanding of the relationship between diet and detoxification, RDNs like Foroutan wonder whether a diet rich in certain nutrients could maximize the detox system’s productivity, vastly improving general health and even athletic performance.

Research into how food, various toxins, and certain lifestyle factors actually affect the detoxification pathways’ performance is still in its infancy. Some studies have shown rapid effects of nutrients on enzymes that help transform toxins; others see days of lag time. In more than one instance, different doses of the same food had opposite affects on the same enzyme. Many of the studies have used cells or animals as their subjects, and RDNs typically refrain from making firm recommendations to patients until evidence-based, peer-reviewed clinical trials show significant support. That said, there are some promising detoxification front-runners, including berries, garlic, turmeric, green tea, and cruciferous vegetables like Brussels sprouts. Plus, these foods are good for you in their own right, and what’s most important is incorporating them into a generally diverse diet.

“A dietary pattern favoring whole, unprocessed, plant-based foods and the removal or reduction of toxic substances in one’s environment is a two-pronged approach that would seem to have the best overarching scientific underpinning,” the authors of a 2015 review on detoxification concluded.

In the long run, this kind of diet will support all body functions. That’s why the best advice from these experts is nothing you haven’t heard before: Eat more fruits and vegetables—and a greater variety of them. Eat more fiber and protein. Eat less refined sugar, trans fat, and saturated fat. Drink more water. Stefanski also emphasizes healthy sleep patterns, because “sleep allows the body to focus on repairing itself without the added burden of maintaining physical activity or alertness.” And if you you still have questions about detoxification, visit an RDN or doctor—maybe even one who specializes in detoxification pathways—who can assess your toxic and genetic profiles and discuss whether you may benefit from incorporating different foods into your diet.

Focus on nailing the fundamentals of healthy eating, and your performance will improve. You might also support your detoxification processes along the way.